i agree with Mathlegend, its risky for mundo to have 2.1k hp with items as he has low PR and MR. but i 2 agree with the part that you get alot of kills, especially if you have blue:

mundo + blue = 2 sec slow - 2.4 sec cd

nice build

very good build ... but i kinda mix it with some tank items and support ones too... cause mundo can get really good at dps until mid game, but agains't carrys at late game ,its kinda tough gank 5 vs 5 without any defense and hp, i did got a high rate of kill with your build and i liked it , but depending on the enemy team playstyle and heroes its kinda risky !

Now i see how Mundo Cleaver benefits him a lot.

by the way i tried to make Sivir guide but i failed since my mozilla just crashed when i'm typing the skills, items, type, strategy, builds, and others that's Bu LL Sh It... Oh well im lazy now to do it again maybe someday i will post it.
- Ainse

Not bad, not bad at all.. nice h8. ive seen it work though, so i am bias +1
- HeAt